Refrigeration circuit

Abstract

To meet a request for using two evaporators at different setting temperatures to improve cooling performance even when the request is made in a refrigeration circuit including the two evaporators.SOLUTION: A refrigeration circuit 2 includes: a first evaporator 21 and a second evaporator 23; and a first compressor 22 and a second compressor 24. A first passage 201 provided with the first evaporator 21 and the first compressor 22 and a second passage 202 provided with a second evaporator 23 and a second compressor 24 are provided parallel to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to refrigeration circuits. [Background technology]

[0002] As described in Patent Document 1 below, a refrigeration circuit is known in which two evaporators are connected in parallel to one compressor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-222420 Summary of the Invention [Problem to be solved by the invention]

[0004] In the refrigeration circuit disclosed in Patent Document 1, when two evaporators are used simultaneously at different set temperatures, the refrigerant vapor discharged from the evaporator with the higher set temperature increases the internal pressure of the evaporator with the lower set temperature. Because the temperature of an evaporator is determined by the type of refrigerant and its internal pressure, the lower the internal pressure, the lower the temperature, and the higher the internal pressure, for the same type of refrigerant. Therefore, if the internal pressure of the evaporator with the lower set temperature increases, it becomes difficult to cool, resulting in a deviation from the set temperature. Therefore, Patent Document 1 provides pressure regulating valves downstream of each of the two evaporators to adjust the internal pressure of each evaporator.

[0005] As described in Patent Document 1, by providing pressure regulating valves downstream of each of the two evaporators, the internal pressure of each evaporator can be changed independently of each other. This makes it possible to simultaneously set the temperatures of each evaporator to different temperatures, thereby shortening the cooling time.

[0006] However, for example, when one evaporator is used as an air-conditioning evaporator and the other as a chiller for cooling batteries, the set temperatures are different and high cooling performance for the batteries is required. With the technology described in Patent Document 1, the pressure loss caused by the pressure regulating valve may prevent sufficient cooling performance from being achieved, making it impossible to meet the requirements.

[0007] The present disclosure aims to meet the demand for a refrigeration circuit having two evaporators, even when there is a demand for improving cooling performance by using the two evaporators at different set temperatures. [Means for solving the problem]

[0008] The present disclosure relates to a refrigeration circuit comprising a first evaporator and a second evaporator, and a first compressor and a second compressor, in which a first flow path provided with the first evaporator and the first compressor and a second flow path provided with the second evaporator and the second compressor are arranged in parallel. [Effects of the Invention]

[0009] According to the present disclosure, in a refrigeration circuit having two evaporators, even if there is a request to use the two evaporators at different set temperatures to improve cooling performance, the request can be met. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a refrigeration circuit in this embodiment. [Figure 2] FIG. 2 is a flowchart for explaining the operation of the refrigeration circuit shown in FIG. [Figure 3] FIG. 3 is a Mollier diagram for explaining the effect of the refrigeration circuit in this embodiment. [Figure 4] FIG. 4 is a schematic diagram of a refrigeration circuit in a modified example of this embodiment. [Figure 5] FIG. 5 is a flowchart for explaining the operation of the refrigeration circuit shown in FIG. [Figure 6] FIG. 6 is a flowchart for explaining the operation of the refrigeration circuit shown in FIG. [Figure 7] FIG. 7 is a flowchart for explaining the operation of the refrigeration circuit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] The refrigeration circuit 2 in this embodiment is mounted on a vehicle (not shown). As shown in Fig. 1, the refrigeration circuit 2 in this embodiment includes a chiller 21, a compressor 22, an evaporator 23, a compressor 24, and a condenser 25. In this embodiment, the evaporator 23 is used for air conditioning the interior of the vehicle. The chiller 21 is used for cooling a battery mounted on the vehicle.

[0013] The chiller 21 and the compressor 22 are arranged in a first flow path 201. The evaporator 23 and the compressor 24 are arranged in a second flow path 202. The condenser 25 is arranged in a third flow path 203.

[0014] One end of first flow path 201, one end of second flow path 202, and one end of third flow path 203 are connected at connection part P1. The other end of first flow path 201, the other end of second flow path 202, and the other end of third flow path 203 are connected at connection part P2. Therefore, first flow path 201 and second flow path 202 are arranged in parallel with third flow path 203.

[0015] In the first flow path 201, the suction side, which is the upstream side of the compressor 22, is the connection part P1 side, and the discharge side, which is the downstream side of the compressor 22, is the connection part P2 side. In the first flow path 201, the chiller 21 is disposed on the suction side, which is the upstream side of the compressor 22. In the first flow path 201, an expansion valve 31 is disposed on the connection part P1 side, which is the upstream side of the chiller 21. A check valve 32 is disposed on the connection part P2 side, which is the downstream side of the compressor 22.

[0016] In the second flow path 202, the suction side, which is the upstream side of the compressor 24, is the connection part P1 side, and the discharge side, which is the downstream side of the compressor 24, is the connection part P2 side. In the second flow path 202, the evaporator 23 is disposed on the suction side, which is the upstream side of the compressor 24. In the second flow path 202, an expansion valve 33 is disposed on the connection part P1 side, which is the upstream side of the evaporator 23. A check valve 34 is disposed on the connection part P2 side, which is the downstream side of the compressor 24.

[0017] The control unit 5 has, as electrical components, a microcomputer (hereinafter referred to as "mc"), a data transfer circuit, a power supply circuit, and a power supply detection circuit. The mc includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory.

[0018] The control unit 5 receives input of driving information, air conditioning information, and battery cooling information. The driving information is information relating to the driving state of the vehicle in which the refrigeration circuit 2 is installed. The air conditioning information is information relating to the air conditioning state in the passenger compartment of the vehicle in which the refrigeration circuit 2 is installed. The air conditioning information includes information relating to the air conditioning state in the passenger compartment and air conditioning instructions for the passenger compartment. The battery cooling information is information relating to the cooling state of the battery provided in the vehicle in which the refrigeration circuit 2 is installed.

[0019] The control unit 5 outputs control signals for driving the compressor 22, the compressor 24, the expansion valve 31, and the expansion valve 33, respectively.

[0020] Next, the operation of the refrigeration circuit 2 will be described with reference to Fig. 2. In step S01, the control unit 5 determines whether or not there is a cooling request. If there is a cooling request (step S01: YES), the process proceeds to step S02. If there is no cooling request (step S01: NO), the process proceeds to step S03.

[0021] In step S02, control unit 5 determines whether or not there is a request to cool the battery. If there is a request to cool the battery (step S02: YES), the process proceeds to step S04. If there is no request to cool the battery (step S02: NO), the process proceeds to step S06.

[0022] In step S03, the control unit 5 determines whether or not there is a request to cool the battery. If there is a request to cool the battery (step S03: YES), the process proceeds to step S08. If there is no request to cool the battery (step S03: NO), the process proceeds to step S10.

[0023] In step S04, the control unit 5 outputs a control signal to open the expansion valve 31, and outputs a control signal to open the expansion valve 33. In step S05 following step S04, the control unit 5 outputs a control signal to operate the compressor 22, and outputs a control signal to operate the compressor 24. The processing in steps S04 and S05 corresponds to a situation where there is a request to cool the battery and also a request to cool the vehicle interior.

[0024] 3 shows an example of a Mollier diagram when the processing of steps S04 and S05 is performed. The first flow path 201 side is a diagram that passes through S11, S2, S3, and S41. The second flow path 202 side is a diagram that passes through S12, S2, S3, and S42. The processing of steps S04 and S05 drives both the compressor 22 on the chiller 21 side and the compressor 24 on the evaporator 23 side as independent circuits, so that the cooling capacity and the cooling capacity can be controlled individually between the first flow path 201 and the second flow path 202 without affecting each other's refrigerant pressure or refrigerant mass flow rate.

[0025] In step S06, the control unit 5 outputs a control signal to open the expansion valve 31, and outputs a control signal to open the expansion valve 33. In step S07 following step S06, the control unit 5 outputs a control signal to stop the compressor 22, and outputs a control signal to operate the compressor 24. The processing in steps S06 and S07 corresponds to a situation where the vehicle is stopped or running at a low load and there is no need to cool the battery, but there is a need to cool the passenger compartment. This processing corresponds to a situation where only the compressor 24 on the evaporator 23 side is driven, and the cooling capacity is controlled by the compressor 24 and the expansion valve 33.

[0026] In step S08, the control unit 5 outputs a control signal to open the expansion valve 31, and outputs a control signal to open the expansion valve 33. In step S09 following step S08, the control unit 5 outputs a control signal to operate the compressor 22, and outputs a control signal to stop the compressor 24. The processing in steps S08 and S09 corresponds to a situation where there is a request to cool the battery but no request to cool the passenger compartment. This processing corresponds to a situation where only the compressor 22 on the chiller 21 side is driven, and the cooling capacity is controlled by the compressor 22 and the expansion valve 31.

[0027] In step S10, the control unit 5 outputs a control signal to open the expansion valve 31, and outputs a control signal to open the expansion valve 33. In step S11 following step S10, the control unit 5 outputs a control signal to stop the compressor 22, and outputs a control signal to stop the compressor 24. The processing in steps S10 and S11 corresponds to a situation where the vehicle is stopped or running at a low load and there is no request to cool the battery or to cool the passenger compartment. This processing is a processing to stop the refrigeration circuit 2.

[0028] Next, a refrigeration circuit 2A in a modified example of this embodiment will be described with reference to Fig. 4. Since the refrigeration circuit 2A is also mounted on a vehicle (not shown), differences from the refrigeration circuit 2 will be described.

[0029] The refrigeration circuit 2A is obtained by providing a connecting flow path 204 and a switching valve 26 in the refrigeration circuit 2. The connecting flow path 204 is provided to connect the connecting portion P3 of the first flow path 201 and the connecting portion P4 of the second flow path 202. The connecting portion P3 is provided in the first flow path 201 between the chiller 21 and the compressor 22. The connecting portion P4 is provided in the second flow path 202 between the evaporator 23 and the compressor 24.

[0030] The switching valve 26 adjusts the flow rate of the refrigerant flowing through the connecting flow path 204. For example, when the switching valve 26 is opened, the refrigerant flows through the connecting flow path 204, and when the switching valve 26 is closed, the refrigerant does not flow through the connecting flow path 204.

[0031] The control unit 5A receives driving information, air conditioning information, battery cooling information, evaporator temperature information, and chiller temperature information. The driving information, air conditioning information, and battery cooling information have been described above, so further description will be omitted. The evaporator temperature information is information relating to the temperature of the evaporator 23. The chiller temperature information is information relating to the temperature of the chiller 21.

[0032] The control unit 5A outputs control signals for driving the compressor 22, the compressor 24, the expansion valve 31, the expansion valve 33, and the switching valve 26, respectively.

[0033] Next, the operation of the refrigeration circuit 2A will be described with reference to Figures 5 and 6. In step S21, the control unit 5A determines whether or not there is a cooling request. If there is a cooling request (step S21: YES), the process proceeds to step S22. If there is no cooling request (step S21: NO), the process proceeds to step S23.

[0034] In step S22, control unit 5A determines whether or not there is a request to cool the battery. If there is a request to cool the battery (step S22: YES), the process proceeds to step S24. If there is no request to cool the battery (step S22: NO), the process proceeds to step S41 in FIG. 6.

[0035] In step S23, control unit 5A determines whether or not there is a request to cool the battery. If there is a request to cool the battery (step S23: YES), the process proceeds to step S51 in Figure 6. If there is no request to cool the battery (step S23: NO), the process proceeds to step S31.

[0036] In step S24, control unit 5A determines whether the required pressure difference between the required pressure of chiller 21 and the required pressure of evaporator 23 is equal to or less than a threshold value. If the required pressure difference is equal to or less than the threshold value (step S24: YES), the process proceeds to step S25. If the required pressure difference is not equal to or less than the threshold value (step S24: NO), the process proceeds to step S28.

[0037] In step S25, control unit 5A outputs a control signal to open switching valve 26. In step S26 following step S25, control unit 5A outputs a control signal to open expansion valve 31, and outputs a control signal to open expansion valve 33. In step S27 following step S26, control unit 5A outputs a control signal to operate compressor 22, and outputs a control signal to operate compressor 24. The processing from step S25 to step S27 is processing that is performed when the refrigerant temperatures required for air conditioning and battery cooling are close and it is desired to operate either chiller 21 or evaporator 23 while providing the performance of at least one compressor.

[0038] In step S28, the control unit 5A outputs a control signal to close the switching valve 26. In step S29 following step S28, the control unit 5A outputs a control signal to open the expansion valve 31 and a control signal to open the expansion valve 33. In step S30 following step S29, the control unit 5A outputs a control signal to operate the compressor 22 and a control signal to operate the compressor 24. The processing from step S28 to step S30 is equivalent to the processing from step S04 to step S05 described with reference to FIGS. 1 and 2. The processing from step S28 to step S30 corresponds to a situation where there is a demand for cooling the battery and also a demand for cooling the vehicle cabin. The processing from step S28 to step S30 drives both the compressor 22 on the chiller 21 side and the compressor 24 on the evaporator 23 side as independent circuits, so that the cooling capacity and the refrigerant capacity can be individually controlled without affecting each other's refrigerant pressure and refrigerant mass flow rate between the first flow path 201 and the second flow path 202.

[0039] In step S31, control unit 5A outputs a control signal to close switching valve 26. In step S32 following step S31, control unit 5A outputs a control signal to open expansion valve 31, and outputs a control signal to open expansion valve 33. In step S33 following step S32, control unit 5A outputs a control signal to stop compressor 22, and outputs a control signal to stop compressor 24. The processing from step S31 to step S32 is processing to stop refrigeration circuit 2A because there is neither an air conditioning request nor a battery cooling request.

[0040] 6, the control unit 5A determines whether the fin temperature of the evaporator 23 is equal to or higher than the threshold value. If the fin temperature of the evaporator 23 is equal to or higher than the threshold value (step S41: YES), the process proceeds to step S42. If the fin temperature of the evaporator 23 is not equal to or higher than the threshold value (step S41: NO), the process proceeds to step S45.

[0041] In step S42, control unit 5A outputs a control signal to open switching valve 26. In step S43 following step S42, control unit 5A outputs a control signal to close expansion valve 31, and outputs a control signal to open expansion valve 33. In step S44 following step S43, control unit 5A outputs a control signal to operate compressor 22, and outputs a control signal to operate compressor 24. The processing from step S42 to step S44 is processing when there is no demand for cooling the battery and there is a high demand for cooling. Both compressor 22 on the chiller 21 side and compressor 24 on the evaporator 23 side can be driven and used only for cooling, so a demand for strong cooling can be met.

[0042] In step S45, the control unit 5A outputs a control signal to close the switching valve 26. In step S46 following step S45, the control unit 5A outputs a control signal to open the expansion valve 31, and outputs a control signal to open the expansion valve 33. In step S47 following step S46, the control unit 5A outputs a control signal to stop the compressor 22, and outputs a control signal to operate the compressor 24. The processing from step S45 to step S47 is processing when there is no demand for cooling the battery and the demand for cooling is at a normal level. Only the compressor 24 on the evaporator 23 side is driven, allowing normal cooling operation.

[0043] 6, the control unit 5A determines whether the coolant temperature of the chiller 21 is equal to or higher than the threshold value. If the coolant temperature of the chiller 21 is equal to or higher than the threshold value (step S51: YES), the process proceeds to step S52. If the coolant temperature of the chiller 21 is not equal to or higher than the threshold value (step S51: NO), the process proceeds to step S55.

[0044] In step S52, control unit 5A outputs a control signal to open switching valve 26. In step S53 following step S52, control unit 5A outputs a control signal to open expansion valve 31, and outputs a control signal to close expansion valve 33. In step S54 following step S53, control unit 5A outputs a control signal to operate compressor 22, and outputs a control signal to operate compressor 24. The processing from step S52 to step S54 is processing when there is a high demand for cooling the battery and no demand for air conditioning. Both compressor 22 on the chiller 21 side and compressor 24 on the evaporator 23 side can be driven and used only for cooling the battery, so it is possible to respond to strong cooling demands.

[0045] In step S55, the control unit 5A outputs a control signal to close the switching valve 26. In step S56 following step S55, the control unit 5A outputs a control signal to open the expansion valve 31, and outputs a control signal to open the expansion valve 33. In step S57 following step S56, the control unit 5A outputs a control signal to operate the compressor 22, and outputs a control signal to stop the compressor 24. The processing from step S55 to step S57 is processing when the cooling requirement for the battery is at a normal level and there is no air conditioning requirement. Only the compressor 22 on the chiller 21 side is driven, allowing normal cooling operation.

[0046] Next, the transition operation of the control unit 5A will be described with reference to Fig. 7. The transition operation is a general term for operations that prevent malfunctions when transitioning from the various operating states described with reference to Figs. 5 and 6 to other operating states. One example of the transition operation is to prevent the compressor from suctioning a closed circuit. Another example of the transition operation is to prevent unintentional heat exchange from being performed on a heat exchanger that does not have a cooling or cooling request.

[0047] In step S81 in Fig. 7, the control unit 5A determines whether the operating state before the next operating state was one in which the switching valve 26 was closed. The operating states in which the switching valve 26 was closed are the operating states of steps S28 to S30 in Fig. 5, the operating states of steps S31 to S33, the operating states of steps S45 to S47, and the operating states of steps S55 to S57 in Fig. 6.

[0048] If the previous operating state was one in which the switching valve 26 was closed (step S81: YES), the process proceeds to step S82. If the previous operating state was one in which the switching valve 26 was not closed (step S81: NO), the process proceeds to step S85.

[0049] In step S82, control unit 5A determines whether the next operating state is one that opens switching valve 26. The operating states that open switching valve 26 are the operating states of steps S25 to S27 in Fig. 5, the operating states of steps S42 to S44, and the operating states of steps S52 to S54 in Fig. 6.

[0050] If the next operating state is one that opens the switching valve 26 (step S82: YES), the process proceeds to step S83. If the previous operating state is not one that opens the switching valve 26 (step S82: NO), the process proceeds to step S84.

[0051] In step S85, control unit 5A determines whether the next operating state is one that opens switching valve 26. If the next operating state is one that opens switching valve 26 (step S85: YES), the process proceeds to step S86. If the previous operating state is not one that opens switching valve 26 (step S85: NO), the process proceeds to step S87.

[0052] In step S83, the control unit 5A executes the first transition operation. In the process of step S83, the switching valve 26 is changed from a closed state to an open state, and therefore the first transition operation is an operation that prevents unintentional heat exchange from being performed in a heat exchanger that has no cooling or cooling demand.

[0053] In the first transition operation in which the operation state of steps S28 to S30 is transitioned to another operation state, the switching valve 26 is opened, and then the expansion valves 31 and 33 are closed as necessary.

[0054] In a first transition operation in which the operation state transitions from steps S31 to S33 to steps S25 to S27, the control unit 5A opens the switching valve 26 and drives the compressors 22, 24. The order of operation of the switching valve 26 and the compressors 22, 24 is arbitrary.

[0055] In a first transition operation in which the operation state transitions from steps S31 to S33 to steps S42 to S44, the control unit 5A first closes the expansion valve 31 and opens the switching valve 26. The order of operation of the expansion valve 31 and the switching valve 26 is arbitrary. Thereafter, the control unit 5A drives the compressors 22 and 24. The order of operation of the compressors 22 and 24 is arbitrary.

[0056] In another example of the first transition operation in which the operating state of steps S31 to S33 transitions to the operating state of steps S42 to S44, the control unit 5A first drives the compressor 24. Then, the control unit 5A closes the expansion valve 31 and opens the switching valve 26. Then, the control unit 5A drives the compressor 22.

[0057] In the first transition operation in which the operation state transitions from steps S31 to S33 to steps S52 to S54, the control unit 5A first closes the expansion valve 33 and opens the switching valve 26. The order of operation of the expansion valve 33 and the switching valve 26 is arbitrary. Thereafter, the control unit 5A drives the compressors 22 and 24. The order of operation of the compressors 22 and 24 is arbitrary.

[0058] In another example of the first transition operation in which the operation state of steps S31 to S33 transitions to the operation state of steps S52 to S54, the control unit 5A first drives the compressor 22. Then, the control unit 5A closes the expansion valve 33 and opens the switching valve 26. Then, the control unit 5A drives the compressor 24.

[0059] In the first transition operation in which the operation state of steps S45 to S47 transitions to the operation state of steps S25 to S27, the control unit 5A opens the switching valve 26 and drives the compressor 22. The order of operation of the switching valve 26 and the compressor 22 is arbitrary.

[0060] In the first transition operation in which the operation state of steps S45 to S47 is transitioned to the operation state of steps S42 to S44, the control unit 5A first closes the expansion valve 31 and opens the switching valve 26. Thereafter, the control unit 5A drives the compressor 22.

[0061] In the first transition operation in which the operation state of steps S45 to S47 transitions to the operation state of steps S52 to S54, the control unit 5A first opens the switching valve 26 and drives the compressor 22. Thereafter, the control unit 5A closes the expansion valve 33.

[0062] In another example of the first transition operation in which the operation state of steps S45 to S47 transitions to the operation state of steps S52 to S54, the control unit 5A first opens the switching valve 26 and closes the expansion valve 33. Thereafter, the control unit 5A drives the compressor 22.

[0063] In the first transition operation in which the operating state of steps S55 to S57 transitions to the operating state of steps S42 to S44, the control unit 5A first opens the switching valve 26 and drives the compressor 24. The order of operation of the switching valve 26 and the compressor 24 is arbitrary. Thereafter, the control unit 5A closes the expansion valve 31.

[0064] In another example of the first transition operation in which the operation state of steps S55 to S57 transitions to the operation state of steps S42 to S44, the control unit 5A first opens the switching valve 26 and closes the expansion valve 31. Thereafter, the control unit 5A drives the compressor 24.

[0065] In the first transition operation in which the operating state of steps S55 to S57 transitions to the operating state of steps S52 to S54, the control unit 5A first opens the switching valve 26 and drives the compressor 24. The order of operation of the switching valve 26 and the compressor 24 is arbitrary. Thereafter, the control unit 5A closes the expansion valve 33.

[0066] In another example of the first transition operation in which the operation state of steps S55 to S57 transitions to the operation state of steps S52 to S54, the control unit 5A first opens the switching valve 26 and closes the expansion valve 33. The order of operation of the switching valve 26 and the expansion valve 33 is arbitrary. Thereafter, the control unit 5A drives the compressor 24.

[0067] In the first transition operation in which the operation state of steps S55 to S57 transitions to the operation state of steps S25 to S27, the control unit 5A opens the switching valve 26 and drives the compressor 24. The order of operation of the switching valve 26 and the compressor 24 is arbitrary.

[0068] In step S84, the control unit 5A executes the transition operation in the normal order. Since the process of step S84 maintains the switching valve 26 in a closed state, the transition to the next operating state can be made in the order described with reference to FIGS. 5 and 6, for example.

[0069] In step S86, control unit 5A executes transition operation by operating expansion valves 31 and 33. Since the processing in step S84 maintains switching valve 26 in an open state, it is possible to transition to the next operating state by, for example, changing expansion valve 31 from a closed state to an open state and expansion valve 33 from an open state to a closed state.

[0070] In step S87, the control unit 5A executes the second transition operation. In the process of step S87, the switching valve 26 is changed from an open state to a closed state, and therefore the second transition operation is an operation that prevents the compressor from suctioning the part that is in a closed circuit.

[0071] In the second transition operation in which the operating state of steps S25 to S27 is transitioned to another operating state, the control unit 5A drives the switching valve 26, the expansion valves 31 and 33, and the compressors 22 and 24 in a manner suitable for the other operating state. The order in which the switching valve 26, the expansion valves 31 and 33, and the compressors 22 and 24 are driven is arbitrary.

[0072] In the second transition operation in which the operation state of steps S42 to S44 transitions to the operation state of steps S28 to S30, the control unit 5A first opens the expansion valve 31. The control unit 5A then closes the switching valve .

[0073] In a second transition operation in which the operating state of steps S42 to S44 transitions to the operating state of steps S31 to S33, the control unit 5A stops the compressors 22 and 24. The order of operation of the compressors 22 and 24 is arbitrary. The control unit 5A then closes the switching valve 26 and opens the expansion valve 31. The order of operation of the switching valve 26 and the expansion valve 31 is arbitrary.

[0074] In another example of the second transition operation in which the operating state of steps S42 to S44 transitions to the operating state of steps S31 to S33, the control unit 5A stops the compressor 22. The control unit 5A then closes the switching valve 26. The control unit 5A stops the compressor 24 and opens the expansion valve 31. The order in which the compressor 24 and the expansion valve 31 are operated is arbitrary.

[0075] In the second transition operation in which the operation state of steps S42 to S44 transitions to the operation state of steps S45 to S47, the control unit 5A stops the compressor 22. The control unit 5A then closes the switching valve 26. The control unit 5A then opens the expansion valve 31.

[0076] In a second transition operation in which the operation state transitions from steps S42 to S44 to steps S55 to S57, the control unit 5A opens the expansion valve 31. The control unit 5A then stops the compressor 24 and closes the switching valve 26. The order in which the compressor 24 and the switching valve 26 are operated is arbitrary.

[0077] In another example of the second transition operation in which the operating state of steps S42 to S44 transitions to the operating state of steps S55 to S57, the control unit 5A stops the compressor 24. The control unit 5A then opens the expansion valve 31. The control unit 5A then closes the switching valve 26.

[0078] In the second transition operation in which the operation state of steps S52 to S54 transitions to the operation state of steps S28 to S30, the control unit 5A opens the expansion valve 33. The control unit 5A then closes the switching valve .

[0079] In a second transition operation in which the operating state of steps S52 to S54 transitions to the operating state of steps S31 to S33, the control unit 5A stops the compressors 22 and 24. The order of operation of the compressors 22 and 24 is arbitrary. The control unit 5A then closes the switching valve 26 and opens the expansion valve 33. The order of operation of the switching valve 26 and the expansion valve 33 is arbitrary.

[0080] In another example of the second transition operation in which the operating state of steps S52 to S54 transitions to the operating state of steps S31 to S33, the control unit 5A stops the compressor 24. The control unit 5A then closes the switching valve 26. The control unit 5A then opens the expansion valve 33 and stops the compressor 22. The order in which the expansion valve 33 and the compressor 22 are operated is arbitrary.

[0081] In a second transition operation in which the operation state transitions from steps S52 to S54 to steps S45 to S47, the control unit 5A opens the expansion valve 33. The control unit 5A then closes the switching valve 26 to stop the compressor 22. The order of operation of the switching valve 26 and the compressor 22 is arbitrary.

[0082] In another example of the second transition operation in which the operating state of steps S52 to S54 transitions to the operating state of steps S45 to S47, the control unit 5A stops the compressor 22. The control unit 5A then opens the expansion valve 33. The control unit 5A then closes the switching valve 26.

[0083] In the second transition operation in which the operation state of steps S52 to S54 transitions to the operation state of steps S55 to S57, the control unit 5A stops the compressor 24. The control unit 5A then closes the switching valve 26. The control unit 5A then opens the expansion valve 31.

[0084] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise.

[0085] [Note] Notes 1 and 2 below can be combined in any way as long as there is no technical contradiction.

[0086] [Appendix 1] The compressor includes a first evaporator, a second evaporator, a first compressor, and a second compressor, a first flow path 201 provided with a first evaporator and a first compressor; a second flow path 202 provided with a second evaporator and a second compressor, and a refrigeration circuit 2, 2A provided in parallel;

[0087] In this embodiment, a chiller 21 is exemplified as the first evaporator, and an evaporator 23 is exemplified as the second evaporator.

[0088] According to Supplementary Note 1, the first flow path 201, in which the first evaporator and the first compressor are provided, and the second flow path 202, in which the second evaporator and the second compressor are provided, are arranged in parallel, so that even if there is a request to use the first evaporator and the second evaporator at different set temperatures to improve cooling performance, this request can be met.

[0089] According to Supplementary Note 1, the problem of a decrease in refrigerant flow rate due to pressure loss and a decline in cooling performance in the prior art can be solved. There is no need to increase the superheat of the second evaporator, which is a chiller, so there is no decrease in refrigerant flow rate and no decline in cooling performance. There is no need to unnecessarily increase the rotation speed of compressors 22, 24, so there is no increase in flow velocity at the throttling portions of expansion valves 31, 33, and pressure regulation can be performed sufficiently.

[0090] [Appendix 2] Refrigeration circuit 2A according to appendix 1, a connecting flow path 204 is provided to connect a first flow path 201 between the first evaporator and the first compressor and a second flow path 202 between the second evaporator and the second compressor; The connecting flow path 204 is provided with a switching valve 26 that adjusts the flow rate of the refrigerant flowing through the connecting flow path 204 .

[0091] According to Supplementary Note 2, by providing the connecting flow path 204 and the switching valve 26, the first flow path 201 and the second flow path 202 can be controlled independently, and two compressors can send refrigerant to one evaporator, thereby meeting the demands for strong cooling or strong cooling. [Explanation of symbols]

[0092] 2,2A: Refrigeration circuit 21: Chiller (first evaporator) 22, 24: Compressor (1st compressor, 2nd compressor) 23: Evaporator (second evaporator) 25: Capacitor 26: Switching valve 31, 33: Expansion valve 32, 34: Check valve 5, 5A: Control unit

Claims

1. The compressor includes a first evaporator, a second evaporator, a first compressor, and a second compressor, a first flow path provided with the first evaporator and the first compressor; a second flow path provided with the second evaporator and the second compressor, and a refrigeration circuit provided in parallel.

2. 2. The refrigeration circuit according to claim 1, a connecting flow path connecting the first flow path between the first evaporator and the first compressor and the second flow path between the second evaporator and the second compressor; The refrigeration circuit, wherein the connecting flow path is provided with a switching valve for adjusting the flow rate of the refrigerant flowing through the connecting flow path.

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